1. Field of the Invention
The present invention relates to miniature, unmanned aircraft suitable for use in aerial data collection and transmission, and more particularly, to providing on-board ability to vary fuel-to-air ratios to compensate for varying altitude in such aircraft.
2. Description of the Prior Art
Aircraft can play a role in collection and transmission of data. In transmission of data, an aircraft can serve as a relaying station for remotely originating transmissions. In collection of data, aircraft can be used to carry sensors for reconnaissance and other purposes. Uses of aerial reconnaissance for collecting data, such as multispectral imagery for example, are increasing as industries and businesses come to utilize these technologies to enhance productivity of their operations. An exemplary use of aerial imagery is that of precision farming, although many other uses exist. As aerial imagery and other data collection technologies develop, it becomes desirable to decrease cost and increase practicality of airborne platforms used to acquire aerial imagery and other data.
Aerial imagery has traditionally been acquired through manned conventional aircraft and by satellite. Although both types of platforms are effective, both are quite expensive and limited in their abilities. Unmanned aircraft would be vastly more practical and lower in cost for most civilian data acquisition applications.
Model aircraft, remotely controlled by radio frequency signals, have long been utilized by hobbyists among others. This has led to remotely controlled model aircraft being suggested for use in aerial data collection. U.S. Pat. No. 6,062,176, issued to Lee Berger on May 16, 2000, and U.S. Pat. No. 5,537,909, issued to Arthur J. Schneider et al., both describe use of model or miniaturized aircraft in data imagery acquisition.
Conventional model or miniaturized aircraft typically utilize carbureted single cylinder, two or four stroke cycle reciprocating piston engines. Fuel-to-air ratios are established on the ground by adjusting screw type jets in the carburetor. Once set, such adjustments permit optimized conditions for flight within an altitude window on the order of two thousand feet or so. This satisfies the needs of hobbyists and many other applications for miniaturized aircraft. Most hobbyist use of model aircraft is limited to line of sight control and to the range of radio control devices presently in use, so that an altitude window of two thousand feet is not objectionable. However, there are applications for miniaturized aircraft which fly at much greater altitude from the launch or take off point than two thousand feet.
One specific example will be set forth. Government authorities investigating water resources may wish to obtain aerial imagery of large tracts of land to determine levels of ground water, as reflected by vigorousness of surface vegetation. It may be that comparing images with corresponding images taken at other times will yield the sought information. It would be possible for one image to cover a large land area, with little need for high resolution which would ordinarily be obtained by maintaining flight altitudes within two thousand feet above the ground. Rather, it may be desirable to conduct image acquisition at, for example, five thousand feet or ten thousand feet above the ground.
Operation at these altitudes causes problems when using conventional model aircraft as image acquisition platforms. Manual adjustment of fuel-to-air ratios limits aircraft operation to a predetermined altitude level, such as two thousand feet, which may fall well short of a desired flight altitude. Operating an aircraft above the predetermined limit will likely result in failure of engine operation. Even if the engine can operate, efficiency will be adversely affected, which will limit range of the aircraft.
If this limitation were overcome, the field of commercial unmanned aerial image acquisition would benefit greatly from being able to utilize engines and controls and other components which have been engineered and are readily available on the commercial market for data acquisition. This would greatly minimize costs of obtaining certain useful forms of aerial imagery. There exists a need to adapt existing model aircraft engines to extend the attainable altitude of the aircraft.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention addresses the above described need by enabling automatic, xe2x80x9con-the-flyxe2x80x9d adjustment of fuel-to-air ratios in miniature aircraft which utilize engines, servomechanisms, and other components commercially available to the hobbyist and other radio controlled or model aircraft market. Aircraft provided with this ability enable low cost miniature, unmanned aircraft to be used in obtaining imagery and other data and in transferring data. Transferred data can be that obtained by sensors aboard the miniature aircraft, or alternatively, the miniature aircraft may serve as a relay station having receiver and transmitter capability.
Regardless of the precise role and nature of the aircraft, it will be able to take off from the ground and fly to altitudes previously unattainable in model aircraft. Despite constraints of weight limits and provision of data obtaining and transferring apparatus, altitude ceilings up to twenty thousand feet above sea level have been realized with miniature aircraft using the present invention. Therefore, costs of conducting data acquisition and data transfer from aerial platforms flying at altitudes beyond the reach of model aircraft can be brought into line with costs associated with model aircraft. Also, the use of miniature, unmanned aircraft increases safety factors in that the mass of the aerial platform is enormously decreased over even small private aircraft having human pilots. Many private and governmental purposes can thus be served at costs and safety factors previously unrealized.
Accordingly, it is one principal object of the invention to provide miniature, unmanned aircraft with the ability to fly at altitudes considerably greater than those attainable by manually adjusted carburetion systems.
It is another object of the invention to enable aerial platforms having the general nature, costs, and complexity of model aircraft to gather and transfer data previously limited to remotely controlled model aircraft.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.